Shag-rug nudibranch • Aeolidia papillosa

Photo by Todd Carnahan

IdentificationTrue to its name, a dense dorsal covering of somewhat flattened cerata give this nudibranch the furry appearance of a shag rug. While its colouring is usually whitish or brownish, it may also be dull grey, reddish, or pinkish. It also has a bright white triangular to crescent-shaped patch on the head between the ﻿﻿﻿﻿rhinophores﻿﻿﻿﻿ and the oral tentacles. The shag-rug nudibranch can be more than 10 cm long, though it usually measures around 3-5 cm.

Habitat & RangeThe shag-rug nudibranch can be found on rocks, docks, or floats, and is commonly found near its anemone prey (see below). It inhabits the intertidal and subtidal to a depth of 900 m. It is found in both the North Pacific and North Atlantic. in the Pacific Northwest its distribution extends from Alaska to Baja California, Mexico.